Question

Salinity increases in the mid-latitudinal zones.Why?

Answer 1

Sea Surface Salinity: Sea water is about a 3.49% salt solution, the rest is freshwater. The more saline, the denser the seawater. As the range of salt concentration in the ocean varies from about 3.2 to 3.8%, oceanographers refer to salt content as 'salinity', express salt concentration as parts per thousand; 34.9 ppt is the average salinity. As seawater evaporates the salt remains behind, only the freshwater is transferred from the ocean to the atmosphere. A region of excess evaporation, such as the subtropics tends to become salty, while the areas of excess rainfall become fresher. Sea ice formation also removes freshwater from the ocean, leaving behind a more saline solution. Along the shores of Antarctica this process produces dense water. Salinity reflects the workings of the hydrological cycle: the movement of freshwater through the earth/ocean/atmosphere system.